B3 Flashcards
(15 cards)
When in humans is growth most rapid
Infancy and adolescence
What happens to a baby’s brain straight after birth?
Brain is undeveloped in the womb due to it being too big for birth canal.
Brain grows the fastest when born.
What happens to your reproductive organs as you become an adult?
They grow a lot
What parts of plants only grown?
Meristems, e.g. Root tips and stem nodes.
What do the meristems contain?
Stem cells
Name 3 characteristics of these stem cells in the meristems?
They are undifferentiated but can divide to make new that’s that differentiate. However the differentiated plant cells cannot divide due to their thick rigid cell wall.
Thin walls
No chloroplasts and small vacuoles
What is the best way to measure growth, however what are the issues with this?
To measure the dry mass. However the organism must be killed.
Where can scientists get stem cells from?
Early embryos created during IVF because they can still differentiate
Medical research is developing ways of using stem cells to?
Treat parkisons disease
Repair spinal cord
Type 1 diabetes
Grow tissue or Organs
What’s the the ethical issues raised with use of embryonic stem cells?
Spare embryos could of developed into people. But without this research the embryos would be discarded
Explain the difference between adult and embryonic cells
Scientists can get stem cells from bone marrow or umbilical cord blood, which is less controversial. But these stem cells cannot differentiate into as many types of cells as embryonic stem cells
Identify 3 things for GM products
More people can be fed, as GM crops have higher yield
Many people have no problem with GM produce
Most GM crops have been safe so far
Identify 3 things against GM products
Poor farmers may not be able to afford the seeds of GM crops
Those who have problem with eating produce, won’t buy it meaning farmers and markets loose money
Change ecosystem that cannot be reversed
State 3 potential benefits of GM
Solution to feeding the growing population.
Fertilisers and perry died used but many farmers died from exposure to pesticide and damage the soil
Global warming and water shortage limit crop growth
Crops grown to resist pests, use fewer pesticides. Less harmful to environment
Reduce need for fertilisers due to higher yield
Drought resistant crops, reduce need for water
How do organisms grow?
Start off as a undifferentiated stem cell. Divides by mitosis to form cells that can become specialised. This process is called differentiation. These stem cells that can be any cell type.
